1. Field of the Invention
This invention pertains to a bathing preparation comprising colloidal material in a formulation intended to effervesce in bath water. The effervescence aids in dispersal and delivery of the colloidal particle, as well as providing skin stimulation and fatigue relief in its own right. A method of treating skin irritation with the colloidal material is also addressed.
2. Background of the Prior Art
Bathing preparations which dissolve in warm or hot bath water to effervesce by the release of carbon dioxide as a reaction product in order to stimulate the skin and provide fatigue relief are well known. One example is that disclosed in U.S. Pat. No. 4,666,707, the entirety of which is incorporated herein by reference. In this patent, a moisturizer is incorporated in a carbonate salt/acid combination. When dissolved, the carbonate and acid react to release carbon dioxide. The weakly acidic pH of the resulting water keeps CO.sub.2 in solution, prolonging and promoting the effects of CO.sub.2 skin stimulation, synergistically enhanced by the moisturizer.
Other effervescing bath preparations are also known. A fundamental preparation is disclosed in U.S. Pat. No. 4,650,667. A further example is disclosed in U.S. patent application Ser. No. 07/324,885, filed Mar. 17, 1989, allowed. This preparation employs low-cost fumaric acid. Preparations of the type described are in commercial use, and available under the trademark ACTIBATH.RTM. as well as other names.
The treatment of minor skin irritations, and in particular, relief from itching induced by inflammation, disease, trauma and the like, through the water-mediated application of colloidal materials is well known. Prominent among various materials of this type is colloidal oatmeal, commercially available under the mark AVEENO.RTM. from S. C. Johnson Company, as well as from other sources. Hydrophobic starches are also well known in this application, as materials which, when dispersed in water, settle on and desensitize the skin, and provide temporary relief.
In general, the colloidal material treatments are effected by dispersing the colloidal material in bath water, and then bathing in the bath suspension. This method presents a number of problems.
Maximum effectiveness is achieved by thorough dispersion of the colloidal material throughout the bath water. As these materials are generally in powder form, not only is this a physically awkward operation, but thorough dispersion tends to be frustrated by the tendency of these materials to swell, soften and agglomerate upon moistening.
Further, agglomerated particles of this type tend to settle relatively rapidly, according to Stokes Law, which provides a particle's settling rate in a dispersing fluid will be governed by its relative diameter and density as well as the fluid's viscosity and density.
Due to the colloidal nature of this material, it tends to persist in the tub or bathing enclosure even after draining of the water. The greater the degree of agglomeration, the more difficult it may be to remove residual material.
It therefore remains an object of those of skill in the art to secure the fatigue relief benefits of CO.sub.2 skin stimulation and effervescence, and make the benefits of bathing with colloidal material easier to secure.